Consumer packages of the single-use disposable type for beverages or other consumer products are normally produced from laminated packaging material comprising layers of, for example, paper, thermoplastic and aluminum foil. The material is flexible but relatively rigid and is provided with fold or crease lines in order to facilitate reforming or conversion of the material into individual, filled and sealed packaging containers. The necessary, liquid-tight seals are normally realized by heat-sealing, in which event the thermoplastic layers of the packaging material are employed as adhesive or bonding agent. Prior art packaging containers of this type are normally either parallelepipedic (Tetra Brik.RTM.), or of the so-called gable-top type (Tetra Rex.RTM.), and are described in EP 19324 and EP 356831, respectively, to which publications reference is now made. Both the parallelepipedic packaging containers and packaging containers of the gable-top type most generally include four vertical wall panels or side walls with top and bottom panels. Typically, the parallelepipedic containers have two opposite side walls of narrow width and the remaining two side walls are substantially wider than the other side walls. Gable-top containers typically have side walls of substantially equal width.
Parallelepipedic or gable-top packaging containers with four mutually rectangular side wall panels have long been predominant in this type of packaging container which is normally employed for the packing of, for instance, milk, juice or other liquid consumer products. One important reason for this situation is that symmetric packaging containers displaying a substantially rectangular cross-sectional configuration are well-suited for handling, not only by the consumer, but also in robotics or machine handling in connection with production and various types of carton grouping or marshalling. The consumer packages are, for example, normally placed in groups of 18 (3.times.6) packages in trays or cartons which are then provided with lids or are shrink-film wrapped. By adapting the tray size to the size of the marshalled group of packages, a stable and handlable unit will be obtained, since, as a result of the shape of the package, the side wall panels of the individual packaging containers abut closely against one another and afford mutual support.
Thus, while the currently predominant packing configurations enjoy major practical advantages, they have not attained optimum design in view of packaging material consumption in relation to packed volume. In strictly geometric terms, the ideal packaging container configuration from this point of view is the sphere, but for practical reasons, a ball-shaped packaging container is, of course, less suitable. Attempts to minimize material consumption per packed volume by giving an initially substantially parallelepipedic package more or less outwardly bulging wall panels have, however, been made by placing double-tapering secondary wall panels between the original side wall panels (the primary wall panels), as disclosed in EP Patent 277,673. Granted, this procedure reduces the material consumption somewhat, but the packaging container will, with its outwardly bent walls, have a functionally inferior configuration which causes difficulties in handling and in the placing of the package in grouped transport and storage cartons.
Further, in the above-mentioned prior art packaging containers of parallelepipedic configuration, the flat-laid corner flaps which occur in connection with folding and forming must be folded down to and secured at the outside of the packaging container so that they are not inadvertently folded out during handling of the packaging container. A dependable securement of the corner flaps requires that they can be folded down and fixed against a substantially planar surface of at least the same size as the area of the flat-laid corner flap. Arched, curved or angled surfaces make it difficult to reliably seal the corner flaps in a planar position. Projecting or poorly sealed corner flaps readily come loose when the packaging container is being handled and offer particular problems in the packing of the packaging containers into crate or tray shaped group transport containers, since, in such instance, it must be possible for the packages to be pushed or slid down into a relatively narrow and tight space.
Similarly, gable top containers are typically designed to have a volume that is specified by the packager and selected from standard volumes that have been deemed accepted by the consumer market for the product (i.e., pint, quart, half-gallon, gallon, one-half liter, liter, etc.). The surface area of the carton, and particularly the area of the four side walls, the majority of the surface area, is generally fixed for a given container volume. A reduction in the surface area of the gable top container would reduce the amount of material used to form the containers, thereby reducing the cost of the containers, provided the container still has the required volume.
It will be apparent from the foregoing discussion that the need to increase the theoretical volume of contents of the packaging container in relation to the area of consumed packaging material in part runs contrary to two other necessitating factors, i.e. the need of maintaining, substantially planar wall panels for imparting stability and good handling properties to the container, and secondly the need to provide for dependable anchorage possibilities for the corner flaps of parallelepipedic containers. Similarly, the traditional formation of the gable top container is based on having four flat side walls.